Thank you for you're help. You're right, I took public key instead of a private one.
I imported the private and public keys to the second machine and now everthings works correctly. PGP is decrypting and encrypting files as it should.
One thing everyone should be aware of is that the key should be signed before it's Trust is set to Implicit. It took me some time to find this info in manual, while I didn't find it in any discussion on the internet.
The only thing I'm concerned about is that when I signed my private key a message appeared. Why is this message showing up?
As I mentioned everything works just fine. Thank you 4 help!